The pathogenic bacteria Chlamydophila pneumoniae and Porphyromanas gingivalis induce chronic inflammation. Epidemiological studies in humans and mouse models support a role for C. pneumoniae and P. gingivalis in chronic inflammatory plaque accumulation. IHowever, how these pathogens induce and maintain chronic inflammation is not well defined. Proinflammatory cytokines including IL-1B , TNF, and IL-6 play a critical role in chronic inflammation. It is known that human inflammatory vascular plaque is associated with polymorphisms in the IL-1 receptor antagonist gene and that IL-1 plays a role in bacterial induced inflammatory vascular plaque accumulation in mice. IL-1B polymorphisms are also associated with P. gingivalis mediated human inflammatory periodontal disease. In this project we will test the following hypotheses: 1) The induction of IL-1B occurs via a defined mechanism in endothelial cells which leads to stimulation of functional responses in platelets and macrophages; and 2) IL-1 plays a critical role in chronic oral inflammatory bone loss and inflammatory plaque formation that is associated with P. gingivalis chronic infection via cell specific mechanisms. To test these hypotheses we propose the following Aims: Aim 1. To define the mechanism by which 1L1-B is induced in response to P. gingivalis in mouse endothelial cells and how IL-1 B modulates platelet and macrophage function. Aim 2. To define the role of lL-1 and cell specificity in expression in P. gingivalis induced oral inflammatory bone loss in a mouse model. Aim 3. To define the role of IL-1 and cell specificitv in expression in P. gingivalis induced chronic inflammation and plaque accumulation in a mouse model. Project 4 together with Projects 1- 3 will define the role of specific innate immune signaling molecules in P. gingivalis and C. pneumoniae induced inflammatory responses in cells relevant to chronic inflammatory processes, will characterize the roles of these innate immune pathways in inflammatory processes in vivo and define cell specificitv in these responses.